1. (a) Calculate the net work output of a heat engine followi WABCDA (b) What is the net work output of a heat engine that follows path ABDA in the figure above, with a straight line from B to D? WABDA= Note: The units on the y-axis are in terms of 106 N/m². The units on the x-axis are in terms of 10-3 m³. P (106 N/m²)

1. (a) Calculate the net work output of a heat engine followi WABCDA (b) What is the net work output of a heat engine that follows path ABDA in the figure above, with a straight line from B to D? WABDA= Note: The units on the y-axis are in terms of 106 N/m². The units on the x-axis are in terms of 10-3 m³. P (106 N/m²)

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter15: Thermodynamics

Section: Chapter Questions

Problem 14PE: Calculate the net work output of a heat engine following path ABCDA in the figure below.

See similar textbooks

Similar questions

The energy output of a heat pump is greater than the energy used to operate the pump. Why doesn't this statement violate the first law of thermodynamics?
Show that the coefficients of performance of refrigerators and heat pumps are related by COPref=COPhp1. Start with the definitions of the COP s and the conservation of energy relationship between Qh, QC, and W.
Steam to drive an old-fashioned steam locomotive is supplied at a constant gauge pressure of 1.75106 N/m2 (about 250 psi) to a piston with a 0.200-m radius. (a) By calculating pv , find the work done by the steam when the piston moves 0.800 m. Note that this is the net work output, since gauge pressure is used. (b) Now find the amount of work by calculating the force exerted times the distance traveled. Is the answer the same as in part (a)?
In performing 100.0 J of work, an engine discharges 50.0 J of heat. What is the efficiency of the engine?
Consider the processes shown below. In the processes AB and BC, 3600 J and 2400 J of heat are added to the system, respectively. (a) Find the work done in each of the processes AB, BC, AD, and DC. (b) Find the internal energy change in processes AB and BC. (c) Find the internal energy difference between states C and A. (d) Find the total heat added in the ADC process. (e) From the information give, can you find the heat added in process AD? Why or why not?
What is the entropy change of 10 g of steam at 100 when it condenses to water at the same temperature?
Use a PV diagram such as the one in Figure 22.2 (page 653) to figure out how you could modify an engine to increase the work done.
Steam locomotives have an efficiency of 17.0% and operate with a hot steam temperature of 425C. (a) What would the cold reservoir temperature be if this were a Carnot engine? (b) What would the maximum eficiency of this steam engine be if its cold reservoir temperature were 150C ?
A Carnot engine working between two heat baths of temperatures 600 K and 273 K completes each cycle in 5 sec. In each cycle, the engine absorbs 10 kJ of heat. Find the power of the engine.
Consider the process shown below. During steps AB and BC, 3600 J and 2400 J of heat, respectively, are added to the system. (a) Find the work done in each of the processes AB, BC, AD, and DC. (b) Find the internal energy change in processes AB and BC. (c) Find the internal energy difference between states C and A (d) Find the total heat added in the ADC process. (e) From the information given, can you find the heat added in process AD? Why or why not?
Check your Understanding Show that QhQh=QcQc for the hypothetical engine of Figure 4.10 The second property to be demonstrated is that all reversible engines operating between the same two reservoirs have the same efficiency. To this, stat with the two engines D and E of Figure 4.10 (a), which are operating between two common heat reservoirs at temperatures Th and Tc . First, assume that D is a reversible engine and that E is a hypothetical irreversible engine that has a higher efficiency than D. If both engines perform the same amount of work W per cycle, it follows from Equation 4.2 that QhQh . It then follows from the first law that QcQc . Figure 4.10 (a) Two uncoupled engines D and E working between the same reservoirs. (b) The engines, With D working reverse. Suppose the cycle of D is so that it operates as a refrigerator, and the two engines are coupled such that the work output of E is used to drive D, as shown in Figure 4.10(b). Since QhQh and QcQc , the net result of each cycle is equivalent to a spontaneous transfer of heat from the cold reservoir to the hot reservoir, a process second law does not allow. The original assumption must therefore be wrong, and it is impossible to construct an irreversible engine such that E is more efficient than the reversible engine D. Now it is quite easy to demonstrate that the efficiencies of all reversible engines operating between the same reservoirs are equal. Suppose that D and E are reversible engines. If they are as shown in Figure 4.10(b), the efficiency of E cannot be greater than the efficiency of D, or second law would violated. If both engines are then reversed, the same reasoning implies that the efficiency of D cannot be greater than the efficiency of E. Combining these results leads to the conclusion that all reversible engines working between same two reservoirs have the same efficiency.
Check Your Understanding Why was it necessary to state that the process of Example 3.5 is quasi-static.